The formation of color photographic images based on the subtractive color method is generally carried out by subjecting a silver halide color photographic material to color development processing using a primary aromatic amine based developing agent in the presence of cyan, magenta and yellow couplers. At this time, the exposed silver halide grains in the color photographic material are reduced by the developing agent and the oxidation products of the developing agent which are produced at the same time undergo a coupling reaction with the couplers to form cyan, magenta and yellow dyes respectively and these form the color photographic image.
5-Pyrazolones in particular have been employed conventionally for magenta couplers of these couplers. However, these couplers have absorptions which are undesired from a color reproduction point of view, and there is a major problem in improving color reproduction of the red system in particular. Most recently, the pyrazolobenzimidazole skeleton disclosed in British Patent 1,047,612, the indazolone skeleton disclosed in U.S. Pat. No. 3,770,447 and the 1H-pyrazolo[5,1-c]-1,2,4-triazole skeleton disclosed in U.S. Pat. No. 3,725,067 have been disclosed as magenta colored image forming skeletons where this unwanted subsidiary absorption is small. Moreover, the imidazopyrazole skeleton disclosed in U.S. Pat. No. 4,500,630 and the 1H-pyrazolo[1,5-b]-1,2,4-triazole skeleton disclosed in U.S. Pat. No. 4,540,654 have also been suggested.
In particular, couplers with a 1H-pyrazolo[5,1-c]-1,2,4-triazole skeleton or a 1H-pyrazolo[1,5-b]-1,2,4-triazole skeleton have an excellent hue and excellent color forming properties and they have already become practical in some products.
Of couplers with a 1H-pyrazolo[5,1-c]-1,2,4-triazole skeleton which have an improved hue, the couplers disclosed in U.S. Pat. No. 4,942,117 have an excellent hue and the disclosure is that the graininess and photographic speed, which are weaknesses of couplers which have the same parent nucleus, approach those of the 5-pyrazolone type couplers and that they have a performance which is satisfactory for practical use.
However, the couplers disclosed in this patent have a poor fastness to light and they are not sufficiently stable for use in color photosensitive materials for print purposes or for slide purposes. The combined use of anti-color fading agents has been employed as a means of improving this aspect of these couplers. This method provides some improvement if an appropriate anti-fading agent is selected, but it is necessary to add a large amount of anti-fading agent with respect to the coupler to provide an adequate effect. The oil soluble component is increased as the amount added is increased and so this ultimately results in an increase of the emulsion film thickness. An increase in the emulsion film thickness results in a decrease in the sharpness of a color photosensitive material, especially with camera materials, and results in a worsening of picture quality. Furthermore, an increase in emulsion film thickness retards the progress of the development of the emulsion layer on the side closest to the support and so impedes any decrease in the development time.